1. Field of the Invention
The present invention relates to a solid for lubrication used for supplementing the moisture of skin and making its slide better during massage, sexual intercourse, etc. and also to a process for manufacturing the same.
2. Description of Related Art
When hand is directly touched to the skin (including the mucous membrane) and the force is applied on massaging, there is a possibility that the skin rubbed by the hand is worn out. In addition, during the sexual intercourse, there is a case where the private parts feel pain or their skin is injured. Thus, among ladies after menopause and convalescent or aged people having inconvenience for moving their body, there are many who worry about that. In order to prevent such a trouble, it is preferred that a lubricant liquid is applied to the skin (or to an insert for the skin) to make the slide better followed by doing massage, intercourse, etc. Lubricant liquid for such a use is receiving public attention recently and has been widely sold by, for example, manufacturers of condom. Such a lubricant liquid is sold by placing in a container such as bottle or tube and used by opening the stopper, receiving an appropriate amount on the hand from the opening of the bottle and applying it to the skin.
In the conventional lubricant liquid, however, it is taken by the hand and then applied to the skin or massaged. Therefore, there are problems that the hand becomes unnecessarily sticky, that the hand or the skin becomes dirty depending upon the applied site causing unsanitary conditions and that the using amount is apt to become large whereby clothing and bed sheet are apt to be stained. Further, when hand and fingers are used for massaging a narrow area, there are inconveniences that a pleasant feel is not always achieved and that the parts are scratched by the nail. Furthermore, there are many cases where the lubricant liquid comes out too much depending upon the way of inclining the tube or the way of squeezing the tube and where the lubricant liquid spills too much when the bottle, etc. are fallen down by carelessness whereby the lubricant liquid is wasted.
Under such circumstances, an object of the present invention is to provide a solid for lubrication which is able to be hygienically used without making the hand unnecessarily sticky and without staining hand, skin, clothing, bed sheet, etc., which is able to be safely massaged with a pleasant touch especially for the parts of narrow area and has no inconvenience of too much coming-out or dropping, and also to provide a process for manufacturing the same.
In order to achieve the above-mentioned object, the following means are adopted.
(1) A solid for lubrication molded into a lump shape where a solid substance for lubrication giving a lubricant liquid upon dissolving in water is used as a main ingredient.
There is no particular limitation for the solid substance for lubrication and its examples are that mainly comprising polyacrylic acid and propylene glycol and that mainly comprising carboxyvinyl, polyacrylic acid and sodium hydroxide. More specific examples are sodium polyacrylate, etc. The same ones may be used in other embodiments as well.
There is no particular limitation for the lump shape and its examples are rod, sphere, disk, a shape of solid soap, rectangular solid and plate.
When the whole solid for lubrication is wetted by water, it is apt to slip when held by hand and is hard to use. Therefore, it is preferred that catching projections for prevention of sliding or uneven shape are/is formed on the surface of the solid for lubrication at least at the site to be held by hand. The similar slide-proof effect is achieved by making into such a constitution that the surface of the solid for lubrication at least at the site to be held by hand is covered by a water-insoluble cover and the said solid is held by hand over the said cover. That is the same in other means as well.
(2) A process for the manufacture of a solid for lubrication where water is added to particles of a solid substance for lubrication giving a lubricant liquid upon dissolving in water and kneaded and the kneaded substance is molded into a lump shape.
Although there is no particular limitation for the amount of water added, the ratio of 1-3 part(s) to 1 part of the particles of the solid substance for lubrication is preferred. This is because, when the amount of water is too small, the solid for lubrication becomes too hard, while, when it is too much, the said solid becomes too soft. Although there is no particular limitation for water, hardening rarely takes place in the case of pure water and, therefore, it is preferred to contain a very small amount of divalent or higher metal salt (common tap water satisfies such a condition). Examples of the metal salt are sodium salt, magnesium salt and potassium salt.
Kneading is not limited to a particular method and, although a rotary motion using a rotary mixer may be adopted, it is preferred in view of little frictional heat to carry out in a manner of, such as, mochitsuki (pounding of steamed rice using mortar and pestle) using a stamping mixer. There is no particular limitation for the method of making into a lump shape and its examples are extrusion molding (followed by cutting or slicing into a predetermined size), injection molding and press molding.
(3) A process for the manufacture of a solid for lubrication where a binder is added to particles of solid substance for lubrication giving a lubricant liquid upon dissolving in water and mixed and the mixed substance is subjected to a compression molding to give a lump shape.
Examples of the binder are paste, sodium carbonate and sodium sulfate. There is no particular limitation for a compression molding and, for example, that may be carried out by means of tabletting.
(4) A process for the manufacture of a solid for lubrication where a solidifying agent is added to a lubricant liquid to solidify and also to molding into a lump shape.
Examples of the solidifying agent are agar, gellan gum (natural polysaccharides), hydrophilic or hydrophobic polyisocyanate compound, carrageenan, pectin, gelatin, starch and sodium alginate. Here, the term solidifying includes gelling. There is no particular limitation for a method of molding into a lump shape and its examples are extrusion molding (followed by cutting or slicing into a predetermined size), injection molding and press molding.
When a solidifying agent has a property that it solidifies when dissolved in water, heated and the cooled such as agar, gellan gum, carrageenan and xanthan gum, heating may be carried out after adding a solidifying agent to a lubricant liquid although it is preferred to add a solidifying agent after heating a lubricant liquid.
Although there is no particular limitation for a lubricant liquid, that which is prepared by dissolving the above-mentioned solid substance for lubricant liquid in water is appropriate.
(5) A process for the manufacture of a solid for lubrication where a solid substance for lubrication giving a lubricant liquid upon dissolving in water is dissolved in water and the resulting dissolved matter in a gel form is molded into a lump shape.
Advantages of the process is that granular lumps are hardly formed and a uniform solid substance for lubrication without non-homogeneity can be manufactured. There is no particular limitation for a method for the dissolving and an example is a method where a solid substance for lubrication is dissolved by a gradual addition to water using a rotary mixer equipped with a stirrer.
(6) A solid for lubrication which is molded in a lump shape and gives a lubricant liquid when dissolved in water.
With regard to the main ingredient of the solid for lubrication, the solid substances for lubrication mentioned in the above-mentioned means (1) may be exemplified. In addition, as will be exemplified in the Examples given later, various kinds of additives and antiseptics may be added. With regard to the addition as such, that is same in the solid for lubrication in the above-mentioned means (1) as well.
Although there is no particular limitation for the hardness of the molded solid for lubrication, it is preferred that the hardness at ambient temperature as measured by a rheometer method is within a range of from 1xc3x97104 to 2xc3x97105 N/m2 and, more preferably, within a range of from 2xc3x97104 to 1xc3x97105 N/m2.
Other objects of the present invention will be apparent when the embodiments given later are understood and will be clearly mentioned in the attached claims. When persons skilled in the art carry out the present invention, they will find many advantages which are not mentioned in the present specification.